Apparatus for giving anesthetics



Dec. 21, '1937. J CARR 2,103,144"

" APPARATUS Fon GIVING ANESTHETICS I Filed June 25, 19:54 '2shams-'sheetr 1 m. man

Dec. 21, 1937. J. CARRE A 2,103,144

APPARATUS FOR GIVING ANESI/'HETICS I i y Filed June 25, 1934 v2Sheets-Sheet-Z 115 .n ,fm/m05 kan Clfre Patented Dec. 21, 1937 j UNITED-fs'rATEgs y f y .21034144 j I. i .l i 1 i, i. PPARATUS FOR GIVING I JeanCarr, Leers, Y

Application June z5, 1934. serial :No.mm f In Fance July 18, 1933 i i sclaims. (o1. ras-isi) i l ture and carbon dioxide which is breathed outduring the anesthesis. Also the known methods and apparatus do not inany special way permit of increasing the partial pressure of theanesthetic, and cf bringing the proportion thereof in the mixl turerapidly to a maximum. Also, by not taking into account the fact thattheconsumption of oxygen varies according to the degree oi anesthesis,these known methods and apparatus do not provide for an addition ofoxygen in the anesthetic mixture which is proportional tothe quantityrequired bythe patient, `such quantity being also proportional tothevolume of water vapour and carbon dioxide breathed-out of the 1ung8 K iOne object oithisinventionis considerably to increase the proportion ofanesthetic inthe mixture given to the patient. Another Objectis toprovide means for supplying automatically.- or semi-automatically tolthe mixture a quantity of oxygen proportional vto the quantity ofcarbon dioxide and moisture expelled; thek said means will preferablyconsist. of oxygen generators and avoid the useof high pressurebottleswhich arek heavy and cumbersome. Another object of this invention`is to provide means for having a ready reserve of air expelled from thelungs and containing a big proportion of carbon dioxide; such reserve isused, in case of necessity, avoiding the use of carbon dioxide pressurebottles. 4.0 Stili another object of the invention is to have in theapparatus a determined direction of iiowv oi.' gas which diners iroxntheusual -ow .of gases in known apparatus. The direction oi the ow of gasesin the apparatus according to the inven- 45 tion is studied in view topermit of: (I) expelling the air contained in the apparatus v.before.starting an operation; (1I) obtaining in a receptacle taneously reducethe concentration of anesthetic 55 in the mask. The mixture of gasesbeing effected at the entrance 'ofv thel maskQand not in areceiver ofthe gases breathed out as in some known devices,` the actionof theanesthetic is either increased or diminished 'at the very instant thepatient requires such action.; On the lcontrary 5 yin most known devicesthe patient is obliged to breathe, the atmosphere contained k,in aAreceiver before any modicationpin the anesthetic as required bythestate ofthe patient can be eiectively obtained. This can be acause ofserious trouble 10 with someanesthetics. l y g In the appended drawingsrvariousforms of construction of the Vapparatus according to thisinvention have been illustrated: Fig. 1 is a 'schematical view of aiirstr form .of l5 the apparatus.' ,r j

Fig. 2 shows a mask for giving anesthetics in connedatmosphere; 'f

Fig.` 8 is -asectional viewof afcontrolftapfordistributingtheanesthetic, ij

Fig. 9 is a schematical plan view of asiinplied apparatus for shortanesthesis;

Fig. 1o isa" view to Fig. 9 of the ppaf' :iov

rams 111111181 oprationjthereof,v

Fig; 111s a plan View oiga similarfapparat-iis,v

but for-somewhat longeranesthesis.

Theapparatus according toj Fig. '1 essentially' comprises a mask I ofvery gasftight construe# 35 g tion, a pipe 2' for breathing `ouiafa-,valve l, a. v

bag-reservoir 4 for theatmosphere breathedout. a cock '5 admitting intobag-reservoir 4, pipe" t and suitable'cocks'Tandiorregulating'the flow rof the gas tobebreathed. L Thevalvesand the l pipes are established v tooerftheminimum re' sistance to the breathing: S is Aa rese`rvoir jconstituted by onefor several cartridges' o r the like containing achemical which givesiorthfoxygen by the action of watervapourlandcarbondioxidell* The chemical or chemicals contained `in thereservoir 9 are such that theiquantity of. QXygen produced, whichis inproportion' with the carbon l dioxide and' water'vapouif j`absorbed, "isiny sum-"f cient but.. not in excessive Aquantity"for receiving thebreath-oi! the patient. y A: separate reservoirV l0 containing chemicals'whichjsupply oxygen in case o! yneed byf the controlled action,v of'water supplied `drop, by drop through apparatus Il. is

also provided'. jvaives' lz 'and il. anda cockiil ss make it possible toexpel all the air from the apparatus before utilization. A reservoir Ilfor the anesthetic mixed in the breathed atmosphere is provided. I 8designates a similar reservoir for the anesthetic in case the ilrst oneis quite used up. A second bag-reservoir II provides for keeping inreserve an atmosphere containing a strong 'proportion Vof carbon dioxidein case the latter becomes insufficient in quantity in the mixture forbreathing. A cock I8 controls the bag-reservoir I1. Another cock I9suitably mounted permits of letting the patient breath independently ofthe apparatus at a moments notice if required. The apparatus functionsas follows:` First the operator gathersin the bag I 'I a reserve ofcarbon dioxide. To this end the cock I8 is opened and cock l closed. Thecocks Land 8 are operated so as to insulate from the circuit the oxygenre-` generator 9, the atmosphere being` directed through the return pipe6'. The simultaneous operation of the cocks l and 8; such that cock 'Iis open vwhen cock 8 is shut andy inversely, may be effected by means ofa single handle 20 shown on Fig. 1. By means of the reservoirill aquantity of oxygen .is produced. 'suilicient for filling the bagJ I'I.The patient is made to breathe into the bag I'I, and as soon as theconcentration of carbo'nldioxide in the atmosphere breathed in and outvis such that the respiration becomes ample and quick, the cock i8 isclosed at the end of an expiration, and the cock Sis opened. -The bagI'I now contains an atmosphere with a high proportion of carbon dioxidewhich may be useful later. f

The operator then proceeds to produce in the apparatus an anestheticatmosphereaspure as possible, by expelling all the airv or oxygen whichthe apparatus contains. -This-result kis obtained by opening the.exhaust cock .I4 and .sending through the apparatus acurrent-ofanestheticV from the 'reservoir I5. By the pressure of the anestheticgas the valve ,I3 is `closed against'its useat andthecurrent of gaslexpels all the air from the pipesand mask. Y Y,

The bag`4 is filled ,withgaa then emptied by hand pressure, and filledagain. `The current of anesthetic 'gas expels the air,from`V pipes 8 andthrollgh the valve I2, and cock I4 lthe cocks I and are then operated inorderto send` the current of anesthetic gas tlnough the oxygen regen--verator 9, the air from which. is expelled through valveIZ and cook Il.4The air thus bei'ng'expelled from the apparatus, Vthe cook I4ismanually closed andvalve I 2 is automatically kclosed and theanesthesis can be'gin. g v

, When air is breathed out, thevalve 3 is lifted.

The anesthetic goes intoY the bag reservoir 4, the

` breathes in, thevalve 3 is closed whilst valveslland i3 are open, the.exhaust pipe I4 being closed..

' produced by this apparatus is added tothe oxygen of oxygen. i Y

matically regenerated in the course of respiration.

cock 5 of which is opened. When thepatlent The ratmosphere, which isbreathed ,in passes through cock 8 and apparatus 9where in somechemicals produce oxygen by the action of the steam and carbon dioxideof'vthe expired atmosphere. These products, steam. and ycarbon dioxide,are replaoedby a proportional volume Therefore the oxygen is auto- Ifthe quantity ofV oxygen obtained-through the apparatus 9 is notsumcient,the apparatus III maybe used working in the manner described byadmitting water from the reservoirII the oxygen produced by regenerator9. The volume of oxygen produced from 9 alone or with the help of IIImust maar be Just sumcient'to maintain the respiration. The

f I8 of thebag I'IV isv kept closed. When agfurther quantity ofatmosphere'is expired the valve 3 opens whilst valves I2 and I3 areclosed and the operation is continued as aforesaid.

If'th'e proportion of oxygen is still too much theexplred atmosphere,the handle ZII is operated so as to divert more' or less of the atmosphere through the pipe 8' instead of the apparatus 8.

.If the quantity of carbon dioxide is insufflcient in the atmosphere tobe breathed in, one may use the carbon dioxide mixed lwith oxygencontained in the bag-'reservoir II by opening the cock I 8. Thisoperation will rarely be necessary asthe bag reservoir 4 always'containsa certain proportion of carbon dioxide when'fthe pipe 8f iscorrectlyused as aforesaid.

If the anesthesis becomes too seriousone may -let the patient breathefresh air through cock I8. When the bag-reservoir 4 becomes empty onaccount of the absorption oiane'stheticv by the lungs, a fresh quantityof the gas may `be yintroduced by the reservoir I5,.and when the latterbecomes exhaustedfthereservoir I6 maybe used without disconnecting I5.The theticl by the patient decreaseswith vthe progress of the anesthesisto become null Vwhen the anesthesis is complete.A u k y'I'he apparatuswhich has been described with referecetofFig. 1 can be used withany-anesthetic whichis not modified bythe contact with the chemicalsused `for regeneratingtheoxygen, for` instance withl nitrogenprot'oxide, ethylchloride, and the'like.AVV V f If the concentration ofnitrous oxide inthe inhaled atmosphere i's toog'reat, it-producessaturation .of the blood-whichrenders :the anesthesia by settingapparatus IIl--in a'ct on to add pure oxygen to the anesthetic.

The method ofgiving'anesthetics as described above is eifectedin aconfined atmosphere yand consequentlya perfectly gastight mask must ybeused, of a typeillustrated by'way of Aexample inFigs. 1 and 2. Themaskillustrated byI Fig. 1 comprises al pneurnatieal` tirev or pad 2 I whichensures gas-tight contact around the mouth and nose of the patient, achin-pieceZZ, and straps 23 suitably disposed and tensioned formaintaining the whole mask wellappliedonthe face ofthe patient. whichpermits of examining theminthe'course of the operation. f v

. The'mask illustrated inFig. 2 covers entirely the face of the patientand'is attached by straps 24; it comprises eye-holes Hand a chin-piece26. A finger tube 2l opened at its The eyes ofthe patient remain free,`

end Z8 .allows ,thef 'surgeon to examine the eyesl'v absorption of theanes- V in.k

consequentlyk if the anesthesis tends to Fig. 3 illustrates an oxygenregenerating apparatus which does not contain the chemicals incartridges but has the advantage o! allowing easy renewal of thechemicals used for producing oxygen from carbon dioxide and water, aftereach operation. The apparatus shown in perspective view comprises a box28 containing elements 38 oi cylindrical 4or parallelopipedic shape,'made of successive layers. These elements are impregrated with theoxygen regenerating product. The sides 3l and 32 of the box are leftempty to allow easy lling pf the elements 38. When the apparatus hasbeen charged, the side panels 33 and 34 are tted in, the two other sidesof the box 28 being xed, and thetop and bottom sides of the .box beingformed ofwire xgauze for .the flow of gas. The'box 28 is fitted inside acasing 35, which comprises tworemovable covers31, one

Y on each side', eachcover having a filtering layer on a table orhorizontal support'48; the diierent parts of the apparatus are indicatedby the same reference numerals as in Fig. 1-.

The apparatus illustrated by Figs. 5 to 8 is devised specially fortheuse of nitrogen protoxide, with the use of'oxylithas oxygen regeneratingagent. Oxylith. as here referred to, as achemical oxygenating agent, isan alkaline peroxide having the property oi' disengaging or'evolvingoxygen under theaction of carbonio acid and the water vapor contained inthe atmosphere exhaled by an individual. Among'such alkaline peroxidesmay be mentioned activated sodium peroxide, potassium and sodiumtrioxide and potassium and sodium pentoxide, all of which are capable ofuse after the oxygenating power has been reduced. Thesechemical agentsabsorb the carbonio ac id and water vapor contained in the exhaledatmosphere and then evolve suiiicient oxygen, to maintain respiration,but not to such -great extent as' to reduce the anesthetic proportion inthe mixture inhaled.

The apparatus comprises a supporting cradle 8l. secured to the edge ofthe operation table 82.

The cradle l8| has a shape. adapted to receive the oxylith cylinder orreservoir 83. At one end ofthe cylinderis connecteda pipe 84, by meansof a winged-nut 8 5. -At the other end of the cylinder v83 is connectedthe pipe 88 by means of the winged-nut 81. A collar 88 xed to'orintegral with the cradle 8l carries the central pipe. 88 leading to agas-tight mask. The pipe 88 leads from a three-way cock 18 which isillustrated in detail and in cross-section-in Fig. 8. 'Ihecock 1l isconnected on the one side to the pipe 84 .and on the -other side to theApipe 88.

A bottle 1i of nitrogen protoxide is connected to the central pipe 88 bymeans oi the connection 12 andwinged nut 13. A bottle 14 containing abag reservoir, and additional oxygen producing apparatus of Fig. 1.

tion of anesthetic. `gauze wire or similar material and disposed 'inThis bottle is .here shown Y three-way'cock 18. lA bag-reservoir` 18i'or the reserve of ,anesthetic is connected'to pipe 84. A

cock 88 opening into the air,.and valves 8| and 82,v are provided-forexpellingthe air from the apparatus and for obtaining an'high concentra-The three-way cock 'lofiuustrated separately in Fig. 8 comprises'a`cylindrical casting 83 at thebottom of which isconnected pipe '88..lInside the' casting 83' fits a plug 84 which is milledon a portion. ofits circumference to leave v.only the` solid part 88 extendingnearthebottom of the casting. The casting 83 comprises, in two places ofthe circumference thereof, periorations88 and 81. Two chambers 8 8 and88 formed in... the`jwa ll of the casting receive the ends of .pipes .84and 88. -An axial pin 88 and a'handle8l a'reprovi'ded` for operating thecock. By appropriatelyturning the plug the perforations 88 and 81 can begradulally opened 'or closed. It will, oifcoursebe understood that' eachof the valves 1 and'8 ofFig. 1 may be arranged andconstructed in theform dis- -`closed in Fig. 8. whereby graduated opening of'one oi."Vsaid valves accompanies the corresponding graduated closing of theother, and vice versa.

This apparatus'functions as follows: the operator first makes certainthat there visin the appa: ratus an anesthetic atmosphere which is aspure a's possible, by expelling the air or oxygen from the apparatus.This result is obtained by opening the exhaust pipe 88 and sending aflowof protoxide gas through theapparatus. The valve 82 is closed bythe. pressure of the gas andthecock `18 is operated so as to closepipe84.- The flow of .gas expels the air from the tube 88 andthegmask.The cock 18 is then operated so as to yclose the pipe 88, but to openpipe- 84 and -the ilow of gas expels the air from by-pass11-and pipe 84. The

bag 18 is'lled with gas, then `emptied-by hand Y pressure, and vfilledagain. The gas passes through the oxygen regeneratingcylinder. 83 toexpel-thc f air therefrom andthrough the pipe l88 from which the airescapes by the valveliand the exhaust pipe 88 which can then beclosed..The anesth'esisv thevalve 18 opensf'and illls the bag 18; by inspirationthe valve 181s closed, whilst the `valves 8l. and 82 are open, thecockk88`being of course closed. The-atmosphere from `the bag 18 passesfrom the pipe'84 into' thereservoir 83 wherein thev chemicalproducesoxygenirom the'carbon di-' oxide and water ofthe atmospherebreathed out.

The volume of oxygen thus produced-is ina cer-H tain proportion with thevolume of carbon `dioxide and vapour breathed out. The `regeneraltion ofoxygen is effected automatically. y.The recomposed breathing atmospherereturns into 'the mask through the pipe 88, valves-8Iand82', cock 18 andpipe 88. By afurther expiration, valve 8 2l closes whilst valve 18opensr and the same ope" eration is performed. .I i' the quantity ofoxygen producedl in the reservoir 83 is insumcient, one

must use `the mixture ofoxygen andcarbon di-V oxideicontained inreservoir 14, and determine the proportionsfproperly.

If the quantity of oxygen from the reservoirv 83 becon`1es too highinproportionto the protox-f f ide,cock..18 is turned soas to closepartially or 75 totally the pipe 88. In this manner part of the aspiredatmosphere or the whole ot it does not pass through the reservoir `63.In this latter case the atmosphere is breathed out into the reservoir 19through the pipe 04 and is breathed in again directly through the cock10 and the` pipe 69 without passing through the reservoir 63 or thepipe60. By simply turning the handle 9| one may control the openings ofpipes 64 and 60, and the action of the reservoir 63 for obtaining asmaller or higher proportion of oxygen, and inversely of carbon dioxidelin the anesthetic.

If on the other hand the proportion of carbon dioxide in the anestheticatmosphere is insilill-l cient, one may use the reserve of carbondioxide and'oxygen contained in bottle 14, or simply reduce theproportion of oxygen. l

If the anesthesis becomes too deep, one may open communication with theouter atmosphere near the mask, or else one may dilute theprotoxide ofnitrogen in the mixture by vopening the cock the air which thus breathedin dilutes the protoxide. 0

The apparatus illustrated by Figs. 9 to 1v1 is devised specially forshort anesthesis, such asis required for instance for extracting atooth, inclsing an abscess, and the like. Although this apparatus isdestined to be used specially with nitrogen protoxide and oxylith withother chemicals or not, one may also use same with other anestheticssuch-as ethyl chloride, and the like.

For these anestheses of short duration, it is required to obtaincomplete anesthesia, by means of a high concentration of anesthetic inthe atmosphere to be breathed, the anesthesis being stopped as soon asthis result is obtained. The maintaining of the anesthesis not beingrequired in this case, the parts of the apparatus designed to' prolongthe anesthesis can be dispensed with. Namely, the members (bags,bottles) for having a reserve of carbon dioxide and of oxygen and thecircuit with the valves may be dispensed with. However, with thisapparatus can be used sparklets of nitrogen protoxide, oxygen and carbondioxide which allow to prolong slightly the anesthesis if required. Thepipes are made asshort as possible, and

the dead space, which corresponds to the volume of gas remaining aftereach expirationY between the lips of the patient and the oxygenregenerator, is almost null; the purification of the gas is suflicientat each breath vwithoutV the use of the complete circuit with valves.The apparatus thus simplified for giving anesthetics for a little whileis therefore of reducedweight and volume, and easily portable.

The apparatus of Figs. 9; and 10 essentially comprises: a mask `92-with`pneumatic pad 93 and rings for attaching the mask against the face, ashort p ipe 95 connecting the mask with a three-way cock 96 having anopening 91 to the free air. 'Ihe plug of the cock 96 comprises a fullportion 99 and a hollowed portion 9 8; the operation of the cock iseifected by a handle or wheel or any equivalent'means. A tube |00connects the cock 98 to the oxygen regenerating cartridge |0| whichfunctions for a few minutes. To the tube |00 is connected asmall tube|02l having a threaded end on which can be adapted a bottle |03 of thesparklet type, containingy nitrogeh protoxide. The sparklet is shownwith the nozzle disposed in the middle of the cylindrical body which'facilitates the manipulation thereof. 'I'he oxygen regeneratingcartridge |0| communicates on the one lside with the tube |00 and ontoxide, contains no air.

, I5, to a bag-reservoir the other with the bag-reservoir |04Aforanestheticy atmosphere.

f The oxygen regenerating cartridge which is here shown for oxylith,contains a central vdisc f `ment obliges the gas passing through thecartridge ,to come well into contact with the oxygen regeneratingproduct, and ensure maximum eiliciency. Wire 'gauze or filters ofglass-wool or a of asbestos-woolretain the chemical kinside thecartridge. fThe cartridge |0| having been,'.in course of manufacture,filled with nitrogen pro- The vbag reservoir |00 is `emptied, beforebeing adapted f on the -apparatus.

This apparatus operates as follows: the cock es is tumedso as to closethe tube lan: the

sparklet is then screwed on andthe nitrogen `protoxide fills the lbag|04 through the cartridge 0|; the cock iis'in the position illustratedby Fig-.9. The mask is applied against the face of the patient. At thisstage only the cock 96 still lcontains air.Y To commence the operationof giving the anesthetic, the operator turns the cock in the directionof the arrow Fig. 9. By this operation there is a point 'when the plugcloses the pipe 95 and leaves open the tube |00 Vand the opening 91,asis illustrated in Fig. 1l. During the very short time that thisposition occurs, the protoxide of nitrogen, still under pressure in thebag |04, expels the air from the tube |00 and from the cock through theopening 91. The plug being turned further in the same direction the pipe95 is opened whereas the opening 91 is closed.l This position ismaintained for giving the anesthetic and is illustrated by Fig.` 10. Thereservoir-bag |044 is thereby in communication lwith ythe mask. The gasbreathed iny and breathed out has its ozygen regenerated by passingthrough the cartridge |0| in the manner aforesaid.

As soon as the anesthesislis complete, the operator ,takes the mask awayfrom the face of the patient and immediately -performs the short,painful operation. Iftheanesthesis must be kept on for a short time, itwill however be necessary to stop it as soon as the cartridge |0| isexhausted. If on the `other hand the quantity oi' carbon dioxideisinsufilcient the anesthesis must be stopped.

In the case of operations lasting somewhat longer than thosecontemplated forI this last describedl embodiment of the apparatus, onemay use the same apparatus, but with' the help of extra gas bottles, asillustrated by Fig. 11 of the drawings. If the quantity of carbondioxide, or of nitrogen protoxide, or of oxygen is insufflcient in themixture, one may with this apparatus immediately usev an extra sparkletof bottle containing one of these gases respectively. With-reference toFig. 11, a pipe of small gauge, |05, is connected to tube |00.y The pipe|05 leads to three branchments |06, ||0, H4, respectively leading toVthree cocks |01, and respectively |08, H2, and IIS, and to a respectivesparklet.` sparklet |09 sparklet- ||3 contains oxygen, and the thirdsparklet ||1 contains ycarbon dioxide. When these sparkletsare openedthe respective bagreservoirs |00, H2, andy I I0 contain the respectivegases. and by means of the respective cocks |01, III, and Hi these gasescan be sent 'I'he first contains anesthetic. The second into theanesthetic apparatus according to the requirements and according to therequired proportions. 'I'he additional sparklets,v cocks and bags arelaid on a table near'to the main apparatus and under the immediatecontrol of the operator.

If the sparklets have a needle valve instead of a tin capsule which hasto be pierced, the individual reservoirs |08, H2, and H6 can bedispensed with, and the required quantity of carbon dioxide, nitrogenprotoxide or of oxygen can be sent directly into the main reservoir |04.

Having now fully described my said invention, what I claim and desire tosecure by Letters Patent, is:

1. An apparatus for giving anesthetics in a confined atmosphere,comprising in a closed circuit, successively in the direction of theilow of gas: a main circuit and a shunt circuit, cocks in each circuitafter the branchment of said shunt circuit, a common means for operatingsaid two cocks whereby the one cock is closed when the other is opened,and whereby said cocks are opened and closed progressively, an oxygenregenerating apparatus in said shunted portion of the main circuit, anoxygen producing apparatus connected to said shunt circuit, a cockbeyond the shunt circuit allowing communication with the free air, andplaced immediately before a connection with a source of anesthetic underpressure, valves permitting the said determined direction of ilow ofgas, a connection between the said closed circuit and the mask, and acock for closing said last mentioned connection and for communicatingsaid mask with the free air.

2. An apparatus for giving anesthetics in a confined atmosphere,comprising in a closed circuit, a connection, with a cock, to abag-reservoir for a reserve of pure anesthetic atmosphere, a shuntedportion of the main .circuit and a shunt circuit, cocks in each circuitafter the branchment of said4 shunt circuit, a common means foroperating said two cocks whereby the one cock is closed when the otheris opened, and whereby said cocks are opened and closed progressively,an oxygen regenerating apparatus in said shunted portion of the maincircuit, an oxygen producing apparatus connected to said allowingcommunication with the free air, a bag-reservoir for a reserve ofexpired atmosphere and sources .of anesthetic under pressure'connectedto the main circuit immediately before the connection from the said maincircuit to the mask, and means for closing said last mentionedconnection and for communicatingsaid mask with the iree air.

3. An apparatus for-giving anesthetics in a confined atmosphere,including an air excluding mask, a single conduit leading therefrom, a

shunt circuit, a cock beyond the shunt circuit Y.

closed circuit conduit in communication with the single conduit remotefrom the mask, a controlv` valve in the single conduit operable to placethe mask in communication with. the atmosphere or with the closedcircuit conduit at will, automat-v ically opening valves in the closedconduit permitting gaseous ow in one direction only, an an-lv estheticgas container in communication with the closed circuit, a manuallycontrolled air vent valve in the'closed circuit beyond the containerinthe direction oi gaseous now, an anesthetic gas reservoir in the closedconduit beyond the' air vent valve, and an automatically opening valvein the closed circuit -conduit between the air venty valve andanesthetic gas reservoir, whereby on opening the atmospheric` ventlvalve and closing the control' valve the'anestheticfgas from thereservoir may be forced through the closed circuit conduit to clear thelatter of air and to charge the anesthetic gas container, saidanesthetic gas container being open to the ex- V halations of thepatient in the use of the apparatus for giving anesthetics, a by-pass inthe closed conduit beyond the anesthetic gas container in the directionof gas ow, and simultaneously -and oppositely acting valves controllingthe cosed conduit and by-pa'ss conduit to direct the gas iiow whollythrough the by-pass conduit, wholly through the closedvconduit, orpartially through each, and an oxygen regenerat ing apparatus in theby-pass conduit, whereby upon opening the by-pass conduit oxygen is vautomatically regenerated during the course of respiration in theuse ofthe apparatus.

JEAN CARR.

